WD Begins to Ship Hard Drives with 3TB Capacity.

Western Digital on Tuesday started to officially sell internal hard disk drives with capacities up to 3TB. The new hard drives belong to Caviar Green family and hence do not provide high performance, but are designed mostly for data storage purposes. In order to address systems with non-EFI firmware (the vast majority of PCs already in use), WD will bundle a special controller that will allow usage of 2.5TB and 3.0TB drives on older computers.

The hard disk drives (HDDs) with higher than 2.19TB capacity have to use 4KB sectors (up from 512 bytes on the vast majority of current drives), 64-bit operating system, new logical block addressing (LBA) standard along with new UEFI (universal extensible firmware interface) replacement for BIOS (basic input-output system). While it is not hard to install a 64-bit operating system onto any more or less new personal computer, changing a mainboard with BIOS onto a mainboard with UEFI is a problem for a majority of PC owners with systems older than one year. One of the solutions is to utilize a special controller for large-capacity hard disks.

WD is bundling its WD Caviar Green 2.5TB and 3TB hard drives with an Advanced Host Controller Interface (AHCI)-compliant Host Bus Adapter (HBA), which will enable the operating system to use a known driver with correct support for large capacity drives.

WD Caviar Green 3TB hard disk drive is based on four 750GB platters. The drive features Serial ATA-300 interface, 64MB of cache, and comes in industry-standard 3.5" form-factor. Western Digital declares 15ms average read seek, 5.5ms average latency. The spindle speed of Caviar Green 3TB is slightly higher than 5400rpm. WD claims that the novelty can consume up to 10.75W to spin up the drive, up to 6.25W during seek, up to 5.5W in idle mode and up to 1W in stand by.

WD Caviar Green 2.5TB hard drives (model number WD25EZRSDTL) and 3TB hard drives (model number WD30EZRSDTL) are available now in the U.S. at select resellers and distributors. MSRP for the WD Caviar Green 2.5TB hard drive is $189 and the 3TB hard drive is $239

Preview

WD will bundle a special controller that will allow usage of 2.5TB and 3.0TB drives on older computers.

Actually, it will not work with older computers period.
The controller is needed to make it work with newer computers.

have to use 4KB sectors

No, they don't. Seagates 3TB use 512B sectors. WD uses 4kb sectors internally for increased reliablity and reduced overhead, but emulates 512B... so as far as anything but the drives internal components are concerned, it appears as a 512b sector drive.